Not quite an upgrade question ... but in my experience, choosing the UA-ticketed option on the same AC metal (that I would get with an AC ticket), it appears that I still get 100% mileage credit, even on discount fares, rather than the 25% or 50% credit that I would get on the AC ticket.
Can someone confirm that? The AP docs don't explicitly state this scenario, I think.
Last edited by tomh009; Feb 17, 2008 at 7:02 am
Reason: Clarification